From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Rafael J. Wysocki" Subject: Re: [linux-pm] Re: [PATCH] PM: Acquire device locks on suspend Date: Mon, 7 Jan 2008 01:49:47 +0100 Message-ID: <200801070149.47958.rjw@sisk.pl> References: <49505.::ffff:91.5.86.36.1199663162.squirrel@secure.sipsolutions.net> <200801070059.16741.rjw@sisk.pl> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-15" Content-Transfer-Encoding: 7bit Return-path: Received: from ogre.sisk.pl ([217.79.144.158]:34213 "EHLO ogre.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750904AbYAGArs (ORCPT ); Sun, 6 Jan 2008 19:47:48 -0500 In-Reply-To: <200801070059.16741.rjw@sisk.pl> Content-Disposition: inline Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Johannes Berg Cc: Alan Stern , Greg KH , LKML , ACPI Devel Maling List , pm list , Andrew Morton , Ingo Molnar On Monday, 7 of January 2008, Rafael J. Wysocki wrote: > On Monday, 7 of January 2008, Johannes Berg wrote: > > Rafael J. Wysocki wrote: > > > > >> I don't see anything wrong with it. All that will happen is that the > > >> removal will start before the suspend and finish after the resume. > > > > > > In that case, we'll attempt to call the device's .suspend() and .resume() > > > routines, but we shouldn't do that, IMHO. > > > > I don't see anything wrong with that since the driver must be prepared to > > handle that even in the regular case, it's the only thing you can > > guarantee: no more method calls after removal finishes. Am I totally > > misunderstanding things? > > Well, we are towards the end of device removal at this point, having called > bus_remove_device(dev) for example, but still we've got it on dpm_active ... > > This may not be technically wrong (ie. we should be able to recover from > that), but it seems conceptually wrong and with pm_sleep_rwsem in place it > can be avoided. No, it can't, without major complications. Well, I think I'll just send a patch that should work most of the time ... Rafael